The rise in fitness and sports awareness has led to an appreciation of the benefits of exercising in a water environment. The user may be partially or nearly completely submerged.
Two important benefits of water exercise are: 1) the buoyancy effect on the human body where there is an approximately 90% reduction of pressure on articular joint surfaces, and 2) the hydrostatic pressure that enhances venous blood return to the heart. This hydrostatic pressure increases blood circulation within body tissues and decreases joint swelling distal to the inferior vena cava.
A device presently in use is disclosed in U.S. Pat. No. 5,000,710 ('710), issued on Mar. 19, 1991, for a deep water exercise belt, and U.S. Pat. No. 4,689,030 ('030), issued on Aug. 27, 1987, for a hydrotherapy (wet) vest.
The 710 patent discloses a belt that wraps around the torso of the user just above the anterior superior iliac spines of the pelvis (just above the hips). Here the majority of the flotation material is positioned at the back of the user. This placement forces the user to lean forward pushing the spine and the user into hyperextension resulting in complications which limit rehabilitation, sports application, and fitness training. Another limitation of the '710 device is the propensity of the belt to push up into the arm pits that limits the use of the upper extremities and become uncomfortable, to the point of injury, for the user. In such cases, therapeutic exercise and use of the arms for sporting activities becomes difficult or impossible. Yet another limitation of the '710 device and similar belts is the chafing and accompanying injury to the user's body due to the belt moving relative to the body. Another limitation of such belts stems from the belt's exclusive use of circumferential pressure to hold the belt in place--with no ability to resist upward buoyant forces.
The '030 wet vest wraps around the thorax and traverses up over the shoulders and around both sides of the neck. The vest entirely envelopes the axillae and shoulders. The arms and legs are exposed to the water. In order to keep the vest from "riding" upward on the user, a groin strap, which must be narrow due to the human anatomy, is provided. The vest flotation material (and a vest design that allows use of a large amount of such material) lifts the jacket upward towards the surface of the water. A limitation of such a vest is that there is an inordinate and uncomfortable pressure exerted by the groin strap on the groin that causes pain and restricts the user from performing the full range of motion during exercising.
A further limitation is the inability of the user to freely move his or her arms for sport or exercise, and the device pushes the user into an unnatural spinal hyperextension and hip flexation.
Another limitation in such a vest design is that an individual vest can only accommodate a narrow range of human body sizes (usually slender people). The result is that separate vests must be made for individuals of other sizes. This requirement of many vest sizes acts to limit the application and use of such vests.
A limitation common to both the belt and vest designs is that such designs restrict hip flexion and extension due to their innate design characteristics (as described above).
It is an object of the present invention to provide a device that is comfortable to use, that accommodates a wide range of human body sizes, that allows the buoyant force of the flotation material to be distributed around the torso such that the buoyant force of such flotation material acts at the body's anatomic center and buoyancy (which is optimal), and that allows free use and movement of arms and legs for sport and exercise, and that keeps the spine and body posture in a neutral position for exercise.
It is another object of the present invention to provide for a full range of exercise motion for upper and lower extremities that does not restrict hip motion, that does not require the user assume an unnatural posture of spine hyperextension, and that otherwise accommodates the use of sport and water exercise equipment.
It is yet another object of the present invention to provide a water sport and therapy device that is comfortable to use, that does not chafe the user or exhibit restricting pressure or other such limitation.
Another object of the present invention is to provide a water exercise apparatus with an adjustable water resistance.
It is yet a further object of the present invention to provide a water sport life preserver that allows a full freedom of use and motion of the arms and legs.